Recovering dynamic system data

ABSTRACT

Aspects of the invention include creating a collection of control blocks associated with one or more catalogs, each control block including an eye catcher value and a plurality of pointers, creating a collection of recovery control blocks based the collection of control blocks, each recovery control block including a corresponding copy of the eye catcher value and the plurality of pointers, storing a control block memory location for each control block in the collection of control blocks and a recovery memory location for each recovery control block in the collection of recovery control blocks in a recovery table, analyzing the collection of control blocks to determine that a corruption exists, determining a corruption type, the corruption type comprises an infrastructure corruption and or a control block corruption, and initiating a remedial action for the collection of control blocks based at least in part on the corruption type.

BACKGROUND

The present invention generally relates to recovering system dynamicdata, and more specifically, to recovering system dynamic data withoutan outage or delay.

System availability becomes more and more necessary in a global economysince many businesses rely heavily on information technology (IT)systems to conduct business either internally or externally to acustomer or client. That being said, most businesses require their ITsystems to be available continuously without interruption even onnon-business days. System dynamic data is data that must be availablewhen requested, resides in a main memory, and changes regularly within aruntime environment. Common storage is defined as main memory accessibleto multiple applications running on a system. Frequently a computersystem's critical dynamic data resides in common storage so thatmultiple product components can access it. Because the dynamic data isbeing stored in common storage, it opens up the data to being corruptedby others.

SUMMARY

Embodiments of the present invention are directed to acomputer-implemented method for system dynamic data recovery. Anon-limiting example of the computer-implemented method includescreating a collection of control blocks associated with one or morecatalogs, wherein each control block in the collection of control blocksincludes an eye catcher value and a plurality of pointers, creating acollection of recovery control blocks based at least in part on thecollection of control blocks, wherein each recovery control block in thecollection of recovery control blocks includes a corresponding copy ofthe eye catcher value and the plurality of pointers, storing a controlblock memory location for each control block in the collection ofcontrol blocks and a recovery memory location for each recovery controlblock in the collection of recovery control blocks in a recovery table,analyzing the collection of control blocks to determine that acorruption exists, determining a corruption type, wherein the corruptiontype includes one or both of an infrastructure corruption and or acontrol block corruption, and initiating a remedial action for thecollection of control blocks based at least in part on the corruptiontype.

Embodiments of the present invention are directed to a system for systemdynamic data recovery. A non-limiting example of the system includes aprocessor configured to perform creating a collection of control blocksassociated with one or more catalogs, wherein each control block in thecollection of control blocks includes an eye catcher value and aplurality of pointers, creating a collection of recovery control blocksbased at least in part on the collection of control blocks, wherein eachrecovery control block in the collection of recovery control blocksincludes a corresponding copy of the eye catcher value and the pluralityof pointers, storing a control block memory location for each controlblock in the collection of control blocks and a recovery memory locationfor each recovery control block in the collection of recovery controlblocks in a recovery table, analyzing the collection of control blocksto determine that a corruption exists, determining a corruption type,wherein the corruption type includes one or both of an infrastructurecorruption and or a control block corruption, and initiating a remedialaction for the collection of control blocks based at least in part onthe corruption type.

Embodiments of the invention are directed to a computer program productfor system dynamic data recovery, the computer program product includinga computer readable storage medium having program instructions embodiedtherewith. The program instructions are executable by a processor tocause the processor to perform a method. A non-limiting example of themethod includes creating a collection of control blocks associated withone or more catalogs, wherein each control block in the collection ofcontrol blocks includes an eye catcher value and a plurality ofpointers, creating a collection of recovery control blocks based atleast in part on the collection of control blocks, wherein each recoverycontrol block in the collection of recovery control blocks includes acorresponding copy of the eye catcher value and the plurality ofpointers, storing a control block memory location for each control blockin the collection of control blocks and a recovery memory location foreach recovery control block in the collection of recovery control blocksin a recovery table, analyzing the collection of control blocks todetermine that a corruption exists, determining a corruption type,wherein the corruption type includes one or both of an infrastructurecorruption and or a control block corruption, and initiating a remedialaction for the collection of control blocks based at least in part onthe corruption type.

Additional technical features and benefits are realized through thetechniques of the present invention. Embodiments and aspects of theinvention are described in detail herein and are considered a part ofthe claimed subject matter. For a better understanding, refer to thedetailed description and to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The specifics of the exclusive rights described herein are particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features and advantages ofthe embodiments of the invention are apparent from the followingdetailed description taken in conjunction with the accompanying drawingsin which:

FIG. 1 depicts a block diagram of a system for data recovery inaccordance with one or more embodiments of the present invention;

FIG. 2 depicts a block diagram of the chain of control blocks and thechain of recovery control blocks according to one or more embodiments ofthe invention;

FIG. 3 depicts an example recovery table according to one or moreembodiments of the invention;

FIG. 4 depicts a flow diagram of a method for dynamic data recoveryaccording to one or more embodiments of the invention;

FIG. 5 depicts a cloud computing environment according to one or moreembodiments of the present invention;

FIG. 6 depicts abstraction model layers according to one or moreembodiments of the present invention; and

FIG. 7 depicts a block diagram of a computer system for use inimplementing one or more embodiments of the present invention.

The diagrams depicted herein are illustrative. There can be manyvariations to the diagrams or the operations described therein withoutdeparting from the spirit of the invention. For instance, the actionscan be performed in a differing order or actions can be added, deletedor modified. Also, the term “coupled” and variations thereof describehaving a communications path between two elements and do not imply adirect connection between the elements with no interveningelements/connections between them. All of these variations areconsidered a part of the specification.

DETAILED DESCRIPTION

One or more embodiments of the present invention provide a process thatallows corrupted system dynamic data to be detected and recoveredon-the-fly without an outage or a noticeable delay. The system dynamicdata, in some embodiments, can be referred to as control blocks that areutilized in a storage management system. A storage management system isutilized for managing the storage of datasets of a customer. For thesestorage management systems, the system, rather than a user, determinesdata placement and handles data backup, movement, space, and security.The storage management systems create a catalog for each dataset for acustomer. Whenever a catalog is created, the system creates a controlblock. The control blocks include information such as, for example, acatalog name, the device the catalog resides on, a record length of therecords in the catalog, and pointers to other control blocks that areneeded for input/output (I/O) to the catalog. The control blocks for thevarious catalogs in a system are chained together utilizing pointers.However, issues arise when these control blocks are corrupted.Typically, when corruption is detected, the entire system requires areboot which can cause issues with customer access to the system andgenerally, interrupts the customers business operations. Also, with thistype of corruption of the control blocks, the issue is not detected forhours, days, or weeks. When too much time has passed, it can bechallenging to diagnose how the corruption occurred.

One or more embodiments of the present invention address one or more ofthe above-described shortcomings of the prior art by providing processesthat allows corrupted system dynamic data to be detected sooner and thenrecovered with out the need for a reboot of the storage system. One orembodiments of the invention utilizes a protected recovery table and aprotected copy of the dynamic data (e.g., control blocks, etc.) torebuild the corrupted data that resides in a common storage location.Herein, protected storage includes storage that is only accessible bythe application that owns the data. This process allows for thecorruption to be detected almost immediately so that system traces andlogs still hold diagnostic information to determine the cause of thecorruption.

Turning now to FIG. 1, block diagram of a system for data recovery isgenerally shown in accordance with one or more embodiments of thepresent invention. The system 100 includes a catalog engine 102 thatcontrols the storage management system as well as the dynamic datastored therein. The system 100 includes a common storage 104 and aprotected storage 106. The system dynamic data is in the form of controlblocks 120 which reside in the common storage 104 and the control blocks120 are chained together in a collection. Chaining the control blocks120 together is an exemplary configuration and is not intended to limitthe collection of control blocks described herein. The chain of controlblocks 120 and recovery control blocks 122 can also be referred to as acollection of control blocks and recovery control blocks. The controlblocks 120 can be accessed by multiple applications that interact withthe system 100. Since these control blocks 120 can be accessed bymultiple applications at the same time, these control blocks 120 can beserialized for shared or exclusive access. The system 100 also includesa chain of recovery control blocks 122 and a recovery table 124 thatreside in the protected storage 106. These recovery control blocks 122can be utilized to rebuild/repair any corruption to the dynamic data(e.g., control block 120) in the common storage 104. In addition, therecovery table 124 includes pointers to the control blocks 120 in commonstorage 104 so that the control blocks 120 can never be lost even whenthe corruption in common storage 104 includes corruption to any chainpointers.

In one or more embodiments of the invention, the catalog engine 102 canperform the following process steps within the system 100. When eachcontrol block 120 is created in common storage 104, the address of thecontrol block is saved in the recovery table 124 and a copy of thecontrol block 120 is created in the protected storage 106. These copiesof the control blocks 120 are referred to as recovery control block 122.At regular intervals, or on-demand, the system dynamic data is checkedfor corruption. Corruption can also be detected and repaired in errorinterrupt routines that receive control when the catalog engine 102detects a storage reference issue. When corruption is found, therecovery control blocks 122 are utilized to rebuild the control blocks120 in common storage. The chaining of the control blocks 120 and therecovery control block 122 will be described in greater detail in FIG.2.

In one or more embodiments of the invention, the system 100 can besusceptible to two types of corruption that would need to be detected.The first type of corruption includes a chain corruption. The chain issaid to be corrupted when a chain pointer is found to be pointing to aninvalid control block. An eye catcher field in the control blocks can beutilized to verify that the pointers for a chain are corrupted. When achain corruption occurs, the entire chain of control blocks 120 can nolonger be trusted. In this case, the entire chain of control block 120is then serialized for exclusive access and the chain pointers and eyecatcher field/values are restored from the recovery table 124 withoutchecking any additional pointers. Since this repair of the controlblocks is limited to reassigning the pointer and eye catcher values, theexclusive access of the chain of control blocks 120 is held for arelatively short amount of time causing minimal contention on thestorage management system. The second type of corruption includes acontrol block corruption. An individual control block is corrupted whendata in the control block, other than the chain pointers and the eyecatcher values, are found to be invalid. To repair the control blockcorruption, only the individual control block is to be serialized forexclusive access while the common storage control block is repaired fromthe copy in the protected storage.

In one or more embodiments, the catalog engine 102 can be implemented byexecutable instructions and/or circuitry such as a processing circuitand memory. The processing circuit can be embodied in any type ofcentral processing unit (CPU), including a microprocessor, a digitalsignal processor (DSP), a microcontroller, an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA), orthe like. Also, in embodiments, the memory may include random accessmemory (RAM), read only memory (ROM), or other electronic, optical,magnetic, or any other computer readable medium onto which is storeddata and algorithms as executable instructions in a non-transitory form.In one or embodiments of the invention, the catalog engine 102 can beimplemented on the processing system 700 found in FIG. 7. Additionally,the cloud computing system 50 (from FIG. 5) can be in wired or wirelesselectronic communication with one or all of the elements of the system100. Cloud 50 can supplement, support or replace some or all of thefunctionality of the elements of the system 400. Additionally, some orall of the functionality of the elements of system 100 can beimplemented as a node 10 (shown in FIGS. 5 and 6) of cloud 50. Cloudcomputing node 10 is only one example of a suitable cloud computing nodeand is not intended to suggest any limitation as to the scope of use orfunctionality of embodiments of the invention described herein.

FIG. 2 depicts a block diagram of the chain of control blocks and thechain of recovery control blocks according to one or more embodiments ofthe invention. The diagram 200 includes the common storage 104 with thechain of control blocks 202. Each control block 202 includes pointers aswell as an eye catcher (EPEC). The control blocks 202 in common storage104 include forward and backwards chain pointers to complete the chain.In addition, the control blocks 202 include pointers to correspondingrecovery control blocks 204 residing in the protected storage 106. Inone or more embodiments of the invention, the control blocks 202 incommon storage 104 include both forward and backward chain pointers forease of repair. These pointers can be at opposite ends of the controlblocks to help avoid both pointers being corrupted at the same. Therecovery control blocks 204 are also chained forward and back forconvenience. The corresponding control blocks 202 and recovery controlblocks 204 point to each other. In one or more embodiments of theinvention, the corruption detection can be performed frequently. Forexample, the detection can occur every 30 seconds or less.

FIG. 3 depicts an example recovery table according to one or moreembodiments of the invention. The recovery table 124 includes entriesfor two pointers which are the address of both the control block incommon storage and the recovery control block in the protected storage.These addresses mirror the addresses for control blocks 202 in FIG. 2.As shown, entry #1 refers to the first control block in the chain withaddress of ‘00001000’ and the first recovery control block in the chainwith an address of ‘00201000’. The remaining entries (#2, #3, #4) referto the remaining control blocks 202 in the chains found in common andprotected storage. In some embodiments of the invention, system 100 canmaintain a count of the entries in the recovery table 124 that can beutilized as an index to the next available entry. For example, if thecount is 4, then add one to get to the next available entry (e.g., 5).

FIG. 4 depicts a flow diagram of a method for dynamic data recoveryaccording to one or more embodiments of the invention. The method 400includes creating a collection of control blocks associated with one ormore catalogs, wherein each control block in the collection of controlblocks includes an eye catcher value and a plurality of pointers, asshown in block 402. At block 404, the method 400 includes creating acollection of recovery control blocks based on the collection of controlblocks, wherein each recovery control block in the collection ofrecovery control blocks includes a corresponding copy of the eye catchervalue and the plurality of pointers. The method 400, at block 406, alsoincludes storing a control block memory location for each control blockin the collection of control blocks and a recovery memory location foreach recovery control block in the collection of recovery control blocksin a recovery table. The method 400 also includes analyzing thecollection of control blocks to determine that a corruption exists, asshown in block 408. Then, at block 410, the method 400 includesdetermining a corruption type, wherein the corruption type includes oneor both of an infrastructure corruption and a control block corruption.And at block 412, the method 400 includes initiating a remedial actionfor the chain of control blocks based at least in part on the corruptiontype.

Additional processes may also be included. It should be understood thatthe processes depicted in FIG. 4 represent illustrations, and that otherprocesses may be added or existing processes may be removed, modified,or rearranged without departing from the scope and spirit of the presentinvention.

It is to be understood that although this disclosure includes a detaileddescription on cloud computing, implementation of the teachings recitedherein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g., networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported, providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based e-mail).The consumer does not manage or control the underlying cloudinfrastructure including network, servers, operating systems, storage,or even individual application capabilities, with the possible exceptionof limited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forload-balancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure that includes anetwork of interconnected nodes.

Referring now to FIG. 5, illustrative cloud computing environment 50 isdepicted. As shown, cloud computing environment 50 includes one or morecloud computing nodes 10 with which local computing devices used bycloud consumers, such as, for example, personal digital assistant (PDA)or cellular telephone 54A, desktop computer 54B, laptop computer 54C,and/or automobile computer system 54N may communicate. Nodes 10 maycommunicate with one another. They may be grouped (not shown) physicallyor virtually, in one or more networks, such as Private, Community,Public, or Hybrid clouds as described hereinabove, or a combinationthereof. This allows cloud computing environment 50 to offerinfrastructure, platforms and/or software as services for which a cloudconsumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 54A-N shownin FIG. 5 are intended to be illustrative only and that computing nodes10 and cloud computing environment 50 can communicate with any type ofcomputerized device over any type of network and/or network addressableconnection (e.g., using a web browser).

Referring now to FIG. 6, a set of functional abstraction layers providedby cloud computing environment 50 (FIG. 5) is shown. It should beunderstood in advance that the components, layers, and functions shownin FIG. 6 are intended to be illustrative only and embodiments of theinvention are not limited thereto. As depicted, the following layers andcorresponding functions are provided:

Hardware and software layer 60 includes hardware and softwarecomponents. Examples of hardware components include: mainframes 61; RISC(Reduced Instruction Set Computer) architecture based servers 62;servers 63; blade servers 64; storage devices 65; and networks andnetworking components 66. In some embodiments, software componentsinclude network application server software 67 and database software 68.

Virtualization layer 70 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers71; virtual storage 72; virtual networks 73, including virtual privatenetworks; virtual applications and operating systems 74; and virtualclients 75.

In one example, management layer 80 may provide the functions describedbelow. Resource provisioning 81 provides dynamic procurement ofcomputing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricing 82provide cost tracking as resources are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may include applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal 83 provides access to the cloud computing environment forconsumers and system administrators. Service level management 84provides cloud computing resource allocation and management such thatrequired service levels are met. Service Level Agreement (SLA) planningand fulfillment 85 provide pre-arrangement for, and procurement of,cloud computing resources for which a future requirement is anticipatedin accordance with an SLA.

Workloads layer 90 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation 91; software development and lifecycle management 92; virtualclassroom education delivery 93; data analytics processing 94;transaction processing 95; and recovery of system dynamic data 96.

Turning now to FIG. 7, a computer system 700 is generally shown inaccordance with an embodiment. The computer system 700 can be anelectronic, computer framework comprising and/or employing any numberand combination of computing devices and networks utilizing variouscommunication technologies, as described herein. The computer system 700can be easily scalable, extensible, and modular, with the ability tochange to different services or reconfigure some features independentlyof others. The computer system 700 may be, for example, a server,desktop computer, laptop computer, tablet computer, or smartphone. Insome examples, computer system 700 may be a cloud computing node.Computer system 700 may be described in the general context of computersystem executable instructions, such as program modules, being executedby a computer system. Generally, program modules may include routines,programs, objects, components, logic, data structures, and so on thatperform particular tasks or implement particular abstract data types.Computer system 700 may be practiced in distributed cloud computingenvironments where tasks are performed by remote processing devices thatare linked through a communications network. In a distributed cloudcomputing environment, program modules may be located in both local andremote computer system storage media including memory storage devices.

As shown in FIG. 7, the computer system 700 has one or more centralprocessing units (CPU(s)) 701 a, 701 b, 701 c, etc. (collectively orgenerically referred to as processor(s) 701). The processors 701 can bea single-core processor, multi-core processor, computing cluster, or anynumber of other configurations. The processors 701, also referred to asprocessing circuits, are coupled via a system bus 702 to a system memory703 and various other components. The system memory 703 can include aread only memory (ROM) 704 and a random access memory (RAM) 705. The ROM704 is coupled to the system bus 702 and may include a basicinput/output system (BIOS), which controls certain basic functions ofthe computer system 700. The RAM is read-write memory coupled to thesystem bus 702 for use by the processors 701. The system memory 703provides temporary memory space for operations of said instructionsduring operation. The system memory 703 can include random access memory(RAM), read only memory, flash memory, or any other suitable memorysystems.

The computer system 700 comprises an input/output (I/O) adapter 706 anda communications adapter 707 coupled to the system bus 702. The I/Oadapter 706 may be a small computer system interface (SCSI) adapter thatcommunicates with a hard disk 708 and/or any other similar component.The I/O adapter 706 and the hard disk 708 are collectively referred toherein as a mass storage 710.

Software 711 for execution on the computer system 700 may be stored inthe mass storage 710. The mass storage 710 is an example of a tangiblestorage medium readable by the processors 701, where the software 711 isstored as instructions for execution by the processors 701 to cause thecomputer system 700 to operate, such as is described herein below withrespect to the various Figures. Examples of computer program product andthe execution of such instruction is discussed herein in more detail.The communications adapter 707 interconnects the system bus 702 with anetwork 712, which may be an outside network, enabling the computersystem 700 to communicate with other such systems. In one embodiment, aportion of the system memory 703 and the mass storage 710 collectivelystore an operating system, which may be any appropriate operatingsystem, such as the z/OS or AIX operating system from IBM Corporation,to coordinate the functions of the various components shown in FIG. 7.

Additional input/output devices are shown as connected to the system bus702 via a display adapter 715 and an interface adapter 716 and in oneembodiment, the adapters 706, 707, 715, and 716 may be connected to oneor more I/O buses that are connected to the system bus 702 via anintermediate bus bridge (not shown). A display 719 (e.g., a screen or adisplay monitor) is connected to the system bus 702 by a display adapter715, which may include a graphics controller to improve the performanceof graphics intensive applications and a video controller. A keyboard721, a mouse 722, a speaker 723, etc. can be interconnected to thesystem bus 702 via the interface adapter 716, which may include, forexample, a Super I/O chip integrating multiple device adapters into asingle integrated circuit. Suitable I/O buses for connecting peripheraldevices such as hard disk controllers, network adapters, and graphicsadapters typically include common protocols, such as the PeripheralComponent Interconnect (PCI). Thus, as configured in FIG. 7, thecomputer system 700 includes processing capability in the form of theprocessors 701, and, storage capability including the system memory 703and the mass storage 710, input means such as the keyboard 721 and themouse 722, and output capability including the speaker 723 and thedisplay 719.

In some embodiments, the communications adapter 707 can transmit datausing any suitable interface or protocol, such as the internet smallcomputer system interface, among others. The network 712 may be acellular network, a radio network, a wide area network (WAN), a localarea network (LAN), or the Internet, among others. An external computingdevice may connect to the computer system 700 through the network 712.In some examples, an external computing device may be an externalwebserver or a cloud computing node.

It is to be understood that the block diagram of FIG. 7 is not intendedto indicate that the computer system 700 is to include all of thecomponents shown in FIG. 7. Rather, the computer system 700 can includeany appropriate fewer or additional components not illustrated in FIG. 7(e.g., additional memory components, embedded controllers, modules,additional network interfaces, etc.). Further, the embodiments describedherein with respect to computer system 700 may be implemented with anyappropriate logic, wherein the logic, as referred to herein, can includeany suitable hardware (e.g., a processor, an embedded controller, or anapplication specific integrated circuit, among others), software (e.g.,an application, among others), firmware, or any suitable combination ofhardware, software, and firmware, in various embodiments.

Various embodiments of the invention are described herein with referenceto the related drawings. Alternative embodiments of the invention can bedevised without departing from the scope of this invention. Variousconnections and positional relationships (e.g., over, below, adjacent,etc.) are set forth between elements in the following description and inthe drawings. These connections and/or positional relationships, unlessspecified otherwise, can be direct or indirect, and the presentinvention is not intended to be limiting in this respect. Accordingly, acoupling of entities can refer to either a direct or an indirectcoupling, and a positional relationship between entities can be a director indirect positional relationship. Moreover, the various tasks andprocess steps described herein can be incorporated into a morecomprehensive procedure or process having additional steps orfunctionality not described in detail herein.

One or more of the methods described herein can be implemented with anyor a combination of the following technologies, which are each wellknown in the art: a discrete logic circuit(s) having logic gates forimplementing logic functions upon data signals, an application specificintegrated circuit (ASIC) having appropriate combinational logic gates,a programmable gate array(s) (PGA), a field programmable gate array(FPGA), etc

For the sake of brevity, conventional techniques related to making andusing aspects of the invention may or may not be described in detailherein. In particular, various aspects of computing systems and specificcomputer programs to implement the various technical features describedherein are well known. Accordingly, in the interest of brevity, manyconventional implementation details are only mentioned briefly herein orare omitted entirely without providing the well-known system and/orprocess details.

In some embodiments, various functions or acts can take place at a givenlocation and/or in connection with the operation of one or moreapparatuses or systems. In some embodiments, a portion of a givenfunction or act can be performed at a first device or location, and theremainder of the function or act can be performed at one or moreadditional devices or locations.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” and/or “comprising,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, element components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thepresent disclosure has been presented for purposes of illustration anddescription, but is not intended to be exhaustive or limited to the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art without departing from the scope and spiritof the disclosure. The embodiments were chosen and described in order tobest explain the principles of the disclosure and the practicalapplication, and to enable others of ordinary skill in the art tounderstand the disclosure for various embodiments with variousmodifications as are suited to the particular use contemplated.

The diagrams depicted herein are illustrative. There can be manyvariations to the diagram or the steps (or operations) described thereinwithout departing from the spirit of the disclosure. For instance, theactions can be performed in a differing order or actions can be added,deleted or modified. Also, the term “coupled” describes having a signalpath between two elements and does not imply a direct connection betweenthe elements with no intervening elements/connections therebetween. Allof these variations are considered a part of the present disclosure.

The following definitions and abbreviations are to be used for theinterpretation of the claims and the specification. As used herein, theterms “comprises,” “comprising,” “includes,” “including,” “has,”“having,” “contains” or “containing,” or any other variation thereof,are intended to cover a non-exclusive inclusion. For example, acomposition, a mixture, process, method, article, or apparatus thatcomprises a list of elements is not necessarily limited to only thoseelements but can include other elements not expressly listed or inherentto such composition, mixture, process, method, article, or apparatus.

Additionally, the term “exemplary” is used herein to mean “serving as anexample, instance or illustration.” Any embodiment or design describedherein as “exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments or designs. The terms “at least one”and “one or more” are understood to include any integer number greaterthan or equal to one, i.e. one, two, three, four, etc. The terms “aplurality” are understood to include any integer number greater than orequal to two, i.e. two, three, four, five, etc. The term “connection”can include both an indirect “connection” and a direct “connection.”

The terms “about,” “substantially,” “approximately,” and variationsthereof, are intended to include the degree of error associated withmeasurement of the particular quantity based upon the equipmentavailable at the time of filing the application. For example, “about”can include a range of ±8% or 5%, or 2% of a given value.

The present invention may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) having computer readable program instructions thereonfor causing a processor to carry out aspects of the present invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, configuration data for integrated circuitry, oreither source code or object code written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Smalltalk, C++, or the like, and procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The computer readable program instructions may executeentirely on the user' s computer, partly on the user's computer, as astand-alone software package, partly on the user's computer and partlyon a remote computer or entirely on the remote computer or server. Inthe latter scenario, the remote computer may be connected to the user'scomputer through any type of network, including a local area network(LAN) or a wide area network (WAN), or the connection may be made to anexternal computer (for example, through the Internet using an InternetService Provider). In some embodiments, electronic circuitry including,for example, programmable logic circuitry, field-programmable gatearrays (FPGA), or programmable logic arrays (PLA) may execute thecomputer readable program instruction by utilizing state information ofthe computer readable program instructions to personalize the electroniccircuitry, in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the blocks may occur out of theorder noted in the Figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the describedembodiments. The terminology used herein was chosen to best explain theprinciples of the embodiments, the practical application or technicalimprovement over technologies found in the marketplace, or to enableothers of ordinary skill in the art to understand the embodimentsdescribed herein.

What is claimed is:
 1. A computer-implemented method for data recovery,the method comprising: creating a collection of control blocksassociated with one or more catalogs, wherein each control block in thecollection of control blocks comprises an eye catcher value and aplurality of pointers; creating a collection of recovery control blocksbased at least in part on the collection of control blocks, wherein eachrecovery control block in the collection of recovery control blockscomprises a corresponding copy of the eye catcher value and theplurality of pointers; storing a control block memory location for eachcontrol block in the collection of control blocks and a recovery memorylocation for each recovery control block in the collection of recoverycontrol blocks in a recovery table; analyzing the collection of controlblocks to determine that a corruption exists; determining a corruptiontype, wherein the corruption type comprises one or both of aninfrastructure corruption or a control block corruption; and initiatinga remedial action for the collection of control blocks based at least inpart on the corruption type.
 2. The computer-implemented method of claim1, wherein determining that the corruption type is an infrastructurecorruption comprises: analyzing a value of the eye catcher value toverify the one or more pointers in each control block in the collectionof control blocks; determining that the type of corruption is aninfrastructure corruption based on determining that the eye catchervalue is incorrect.
 3. The computer-implemented method of claim 1,further comprising: based on a determination that the type of corruptionis a collection corruption, initiating the remedial action comprises:restoring the collection of control blocks based on the collection ofrecovery control blocks and the recovery table.
 4. Thecomputer-implemented method of claim 3, wherein restoring the collectionof control blocks based on the collection of recovery control blocks andthe recovery table comprises: serializing the collection of controlblocks; and restoring the one or more collection pointers for eachcontrol block in the set of control blocks from the recovery table. 5.The computer-implemented method of claim 1, further comprising: based ona determination that the type of corruption is a control blockcorruption, initiating the remedial action comprises: determining thatat least one field of a corrupted control block in the collection ofcontrol blocks is corrupted; replacing the corrupted control block witha corresponding recovery control block from the collection of recoverycontrol blocks.
 6. The computer-implemented method of claim 1, whereinthe collection of control blocks is stored in a first storage; whereinthe collection of recovery control blocks is stored in a second storage;and wherein the recovery table is stored in the second storage.
 7. Thecomputer-implemented method of claim 6, wherein the first storagecomprises a common storage; and the second storage comprises a protectedstorage.
 8. The computer-implemented method of claim 1, wherein theplurality of pointers comprises a forward pointer and a backwardspointer.
 9. The computer-implemented method of claim 8, wherein theforward pointer is stored in a first memory location in a control block;wherein the backwards pointer is stored in a second memory location inthe control block; and wherein the first memory location and the secondmemory locations are located at opposite ends of the data controlblocks.
 10. The computer-implemented method of claim 1, whereinanalyzing the collection of control blocks to determine that acorruption exists is performed periodically.
 11. A system for datarecovery comprising: a memory having computer readable instructions; andone or more processors for executing the computer readable instructions,the computer readable instructions controlling the one or moreprocessors to perform operations comprising: creating a collection ofcontrol blocks associated with one or more catalogs, wherein eachcontrol block in the collection of control blocks comprises an eyecatcher value and a plurality of pointers; creating a collection ofrecovery control blocks based at least in part on the collection ofcontrol blocks, wherein each recovery control block in the collection ofrecovery control blocks comprises a corresponding copy of the eyecatcher value and the plurality of pointers; storing a control blockmemory location for each control block in the collection of controlblocks and a recovery memory location for each recovery control block inthe collection of recovery control blocks in a recovery table; analyzingthe collection of control blocks to determine that a corruption exists;determining a corruption type, wherein the corruption type comprises oneor both of an infrastructure corruption and a control block corruption;and initiating a remedial action for the collection of control blocksbased at least in part on the corruption type.
 12. The system of claim11, wherein determining that the corruption type is a infrastructurecorruption comprises: analyzing a value of the eye catcher value toverify the one or more pointers in each control block in the collectionof control blocks; determining that the type of corruption is aninfrastructure corruption based on determining that the eye catchervalue is incorrect.
 13. The system of claim 11, further comprising:based on a determination that the type of corruption is aninfrastructure corruption, initiating the remedial action comprises:restoring the collection of control blocks based on the collection ofrecovery control blocks and the recovery table.
 14. The system of claim13, wherein restoring the collection of control blocks based on thecollection of recovery control blocks and the recovery table comprises:serializing the collection of control blocks; and restoring the one ormore collection pointers for each control block in the set of controlblocks from the recovery table.
 15. The system of claim 11, furthercomprising: based on a determination that the type of corruption is acontrol block corruption, initiating the remedial action comprises:determining that at least one field of a first control block in thecollection of control blocks is corrupted; replacing the first controlblock with a corresponding first recovery control block from thecollection of recovery control blocks.
 16. A computer program productfor data recovery comprising a computer readable storage medium havingprogram instructions embodied therewith, the program instructionsexecutable by a processor to cause the processor to perform operationscomprising: creating a collection of control blocks associated with oneor more catalogs, wherein each control block in the collection ofcontrol blocks comprises an eye catcher value and a plurality ofpointers; creating a collection of recovery control blocks based atleast in part on the collection of control blocks, wherein each recoverycontrol block in the collection of recovery control blocks comprises acorresponding copy of the eye catcher value and the plurality ofpointers; storing a control block memory location for each control blockin the collection of control blocks and a recovery memory location foreach recovery control block in the collection of recovery control blocksin a recovery table; analyzing the collection of control blocks todetermine that a corruption exists; determining a corruption type,wherein the corruption type comprises one or both of an infrastructurecorruption and a control block corruption; and initiating a remedialaction for the collection of control blocks based at least in part onthe corruption type.
 17. The computer program product of claim 16,wherein determining that the corruption type is a infrastructurecorruption comprises: analyzing a value of the eye catcher value toverify the one or more pointers in each control block in the collectionof control blocks; determining that the type of corruption is ainfrastructure corruption based on determining that the eye catchervalue is incorrect.
 18. The computer program product of claim 16,further comprising: based on a determination that the type of corruptionis a infrastructure corruption, initiating the remedial actioncomprises: restoring the collection of control blocks based on thecollection of recovery control blocks and the recovery table.
 19. Thecomputer program product of claim 18, wherein restoring the collectionof control blocks based on the collection of recovery control blocks andthe recovery table comprises: serializing the collection of controlblocks; and restoring the one or more collection pointers for eachcontrol block in the set of control blocks from the recovery table. 20.The computer program product of claim 16, further comprising: based on adetermination that the type of corruption is a control block corruption,initiating the remedial action comprises: determining that at least onefield of a first control block in the collection of control blocks iscorrupted; replacing the first control block with a corresponding firstrecovery control block from the collection of recovery control blocks.